A possible alternative to the requirement to host anything is the public interest standard used by the FCC. That disallows particular profanity and porn for public broadcast: https://www.fcc.gov/consumers/guides/obscene-indecent-and-profane-broadcasts presumably since any kid could pick up a broadcast (never mind that they get it all from the internet nowadays)
Is there some point in splitting this hair? The salient aspect of this is political speech. Going into the weeds of this “pornography is speech” nonsense is irrelevant to the larger and more essential point that political speech must not be censored by anyone, because it will result in a warping of our system of governance.